Comparative Effects of the Blood of Different Species of Vertebrates on Egg-Production of Aëdes Aegypti Linn

Abstract

Summary and Conclusions Aedes aegypti feeds on the blood of many species of animals, including man. The object of these experiments was to determine whether there exist significant differences in the nutritive values of the blood of different species of warm- and cold-blooded vertebrates, when fed to Aedes aegypti, using egg-production as the criterion. The number of eggs produced per milligram of blood ingested served as the basis on which to compare the relative values of the various diets. The quantity of blood ingested was determined by weighing the mosquitoes before and after feeding. A uniform group of imagines for use in experiments was obtained by carefully rearing and selecting the larvae, pupae, and adults. All the mosquitoes used were produced under similar conditions and selected in a similar manner. All of these mosquitoes had access to sugar solution in addition to blood, but on sugar solution alone no eggs were produced. In several preliminary observations mosquitoes which had ingested blood-meals from man invariably produced fewer eggs than those which had ingested blood-meals from any of several species of laboratory animals. Very little or no difference was found in the value for egg-production of blood from different human individuals, nor from one individual obtained at different times in relation to the time of ingestion of food by the host. An experiment to obtain data with which to determine more definitely the comparative effects on egg-production of blood from different species of animals appeared to be indicated. Seven lots of mosquitoes were prepared and each lot was fed on the blood of a different species of animal. Records were obtained of the quantity of blood ingested and the number of eggs produced for each of two successive blood-meals by each individual mosquito in each of the seven lots. The results from the 23 to 28 mosquitoes in the different lots were treated statistically. The essential data are summarized in table 1, and the results of the analysis in table 2. The conclusions may be expressed as follows: The blood of different species of animals differs in its effect on egg-production of Aedes aegypti. Significantly greater numbers of eggs are produced on the blood of turtle, frog, canary, rabbit, and guinea pig, than on the blood of man and of monkey, and significantly greater numbers of eggs on the blood of guinea pig, and of frog, than on the blood of canary. The difference in the effect of the blood of man and of monkey on egg-production is probably not significant. The difference in the effect of the blood of rabbit, guinea pig, and frog, on egg-production is probably not significant. The difference in the effect of the blood of turtle and of rabbit on egg-production is probably not significant. The difference in the effect of the blood of turtle and of guinea pig, turtle and frog, canary and turtle, and canary and rabbit, in each case, is probably significant, but is questioned. The writer wishes to acknowledge his indebtedness to Dr. Francis M. Root, now deceased, under whose direction this work was started, and to Dr. Robert W. Hegner and Dr. Justin Andrews under whose guidance it was continued, for their helpful criticism and suggestions.